Lock nut comprising an external shell member cooperatively keyed to a threaded split internal member



Aug. 14. 1956 F. LE BARRON LORD 2,758,626

LOCK NUT COMPRIS G AN EXTERNAL SHELL MEMBER COOPERATIVELY KEYED TTHREADED SPLIT INTERNAL MEMBER Filed om. 20, 41952 2 Sh eets-Sheet l INVEN TOR.

Aug. 14. 1956 F. LE BARRON LORD 2,758,626

LQCK NUT COMPRISING AN EXTERNAL SHELL MEMBER COOPERATIVELY KEYED TO ATHREADED SPLIT INTERNAL MEMBER Filed Oct. 20, 1952 2 Sheets-Sheet 2 INTERNRL MEMBE R EXTERNAL MEMBER INTERNRL ME "BE R EXTERNAL MEMBERINTERNAL MEMBER EXTERNAL MEMBER INVENTOR. 4 M fig x M44.&

United States Patent LOCK COMPRISING AN SHELL MEMBER 'COOPERATIVELYKEYED TO .A THREADED SPLIT Francis Le Barron Lord, Everett, Mass,assignor of onehalflto Eloise' T. R'oe, Pleasantvill'e, N.'Y., andone-half to Arthur B. B'ellwood, Wellesley, Mass., and CharlesBatchelder, Jr., Milton, Mass, and Mary Bertha Byars, Everett, Mass,trustees Application October 20, 1952, SerialjNo. 315,683

3 Claims. (Cl. 151-1 9) 'Generically, the invention relates to lockingand threading devices, and in particular it constitutes improvements inPatent Number 2,443,466 dated lune 15;, 19-43.

Anobject of the invention comprehends a lock nut which can be employedon any conventional stud which,

once it is'threaded home, can notbe shaken loose :through distinction topresent conventional fasteners wherei nfrom 2 to 37%- represents thetotal thread contact area under load.

Additional objects include:

(a) Total resistance to thread stripping;

(b) Lack ofthread distortion under load;

(c) Self-locking action which develops both a trioti on andcompressionlock within the fastener;

(d) Elimination of fatigue failures;

(,2) Minimum of control of thread tolerance.

These and other objects will; be manifest after aperusal of theaccompanying description and drawing.

Briefly described, the lock nut comprises an external member internallytapered large to bottom, the upper being; flanged, the innerboreprovided with a: key having abrupt and bevelled faces,;.and aninternal member-internally threaded, tapered smallto bottomto; mate thebore of the external member, and provided with a keywall also havingabrupt and bevelled faces cooperating with the key of the externalmember. The outer member may have a hex-wrench peripheral surface forease of handling.

In the drawings:

Fig. 1 is a schematic perspective view of the lock nut, with part beingbroken away.

Fig. 2 is a perspective view of the internal member of the lock nut.

Fig. 3 is a top plan view of the lock nut showing the cooperation of thekey and keyway.

Fig. 4 is a cross sectional view taken through lines 4-4 of Fig. 3.

Fig. 5 is an analysis drawing of a modification.

Fig. 6 is an analysis drawing of another modification.

Fig. 7 is still another modification. With reference to the, drawing,the lock nut '5 comprises outer member 6 the outer peripheral surfaceofwhich maybe, for example, duo-hex, with the upper rim portion'beingcrimped or flanged as at 7, while internally member-6 is bored with ataper bore 8 small to bottom. Internally .of the taper bore .8 I providekey 9 having abrupt face 10 and bevelled face 11.

Cooperating with outer member .6 is inner member 12 tapered small tobottom having-an axial slit 13; the confronting ends of the slit havingshoulders 14, which define the bottom of keyway 15 having abrupt face 16and bevelled face 17, which accommodates key '9. It is to be noted that.axial slit 13 is relatively narrower and of less depth than the keyway15 and is provided with parallel sidewalls in contradist-inction to theabrupt and bevelled or-ladial faces of the key for the purpose ofproviding the maximum internal threaded area of inner member 12. Theinnermost face, in relation to axis, of

key 9, is in adjacent relation to the largest diameter of the threads ofinner member 12:. Member 12 is internally and right hand threaded at 18as indicated in Fig. 3'. I may employ a left handthread, however,-i n

which case the abrupt and-bevelled faces of the key and key-way would bereversed.

With reference, to flange 7 of member 5, this is provided in order tohold the members in assembled'relationshipbut other expedients may beemployed forthis purpose-other than a flange or crimp.

'Whcnthe, lock nut istightened on aconventi'onal stud, the key 9 of theouter member implements the threading ofint-ernal member 12' and thelock nut on to the stud.

The abrupt face 10 of key 9 presses on abrupt face 1'6 of the keyserving toadvance the look nut ongand once threaded home, any tendencyof the-nut toloosen: is prevented by the pressing of bevelled face 11 ofkey 9 -011 bevelled face ofkeyway 15, causing inner member 12 to exertgripping pressure throughout its entire internal loosened; yet vibratoryloosening is prevented by the neutral condition of the key and key wayto the axis turn.

In the Fig. 6 modification any force causing the nut to move will causeit to advance in positive or advance relation.

In the modification depicted in Fig. 7 a nut is illustrated which can beeasily removed because moving the nut in a counter clockwise directionlifts the force of the nut away from the screw.

The following advantages and improved results are accomplished by theuse of my lock nut, and for purpose of explication, I give below, bycolumns, first the area in which the advantage or result is accomplishedand secondly, exactly what, by test is demonstratably accomplished:

Characteristic Thread contact area under load.

.Resistance to thread stripping Thread reaction under load.

. Amoimt of thread engagement required.

. Distribution of load within fastener.

.Thread tolerance requirements.

. Distribution of lock-up energy (hold-downthrcad gripping-friction Usein soft materials Practically 100% of total thread area in contactregardless of tolerances on mating members. Both sides of thread incontact. When locked, a practical unitary condition is established.

Threads will not strip.

No thread distortion. Thread surfaces burnish and improve with use.Fastener adjusts itself to wear of mating threads.

% to 1 diameter or approximately 36 that of conventional threads becauseof filling out of thread form and practical establishment of unitarycondition.

Self-locking action develops both a friction and compression lock on allthread surfaces. Load is evenly distributed with the exception of somestress gradient at point of keying. High, local stress con-' centrationsappreciably minimized.

This lock nut approaches elimination of the basic cause of fatiguefailure.

Tightens under vibration. This action can be controlled by the angularrelation of the negative face of the key.

Tolerances are unimportant within wide wide limits. Neither male norfemale member need be closely controlled.

With this look nut hold-down versus thread gripping can be increased ordecreased (to suit specific applications) by changing the taper angle.

Excellent in soft materials because of the (aluminum magnesbasic,practical unitary thread conditions ium plastics). established. Nodamage on insertion.

11. Removal and replace- Procedure: 1. Break relation between tamcnt ofbroken screw pered surfaces; 2. In screw broken piece; member. 3. Insertsame size stud. Simple, fast and inexpensive. No special sizes required.

12. Preloading of screw Mechanical action of this look nut makes member.preloading unnecessary. No load distortion except in unused portion ofthreads.

13. Use with multi-lead Very practical because of the high frictionthreads.

and compression lock on all thread surfaces. Multi-lead thread can nowbe used in load carrying (tensile) and vibratory applications.

In its broader aspects, the invention comprchcnds the employment notonly of the means described but of equivalent means for performing therecited functions. It is desired to reserve the right to effect suchchanges as may come within the scope of the appended claims.

I claim:

1. In combination with a threaded stud, a lock nut comprising anexternal member defining a complete annulus and having an internal boretapering toward the bottom, the external surface being formed forcooperative engagement with a wrench, a key fixed in said bore andhaving an abrupt and a bevelled face, and an inner face, a split annularinternal member extcriorly tapered for mating engagement in said bore,the inner split portion of said internal member having parallelsidewalls and a pair of oppositely disposed shoulders and an enlargedcontinuation of said split portion forming a keyway bottomed on saidshoulders, having abrupt and bevelled faces for mating engagement withthe abrupt and bevelled faces, respectively of said key, internal screwthreads formed on said internal member mating the threads on said stud,and an inturncd flange 0n the upper end of said external member and inabutting engagement with said internal member for holding the latter inposition within said bore, the inner face of said key in approxi- 4 mateadjacent relation to the largest diameter of the threads of saidinternal member.

2. A lock nut comprising an external member dcfining a complete annulusand having an internal bore tapering toward the bottom, the externalsurface of said external member adapted for cooperating engagement witha wrench, a key fixcd in said bore and having two opposing faces in linewith the axis of rotation, a split annular internal member cxteriorlytapered for mating engagement in said bore, the split portion of saidinternal member having parallel sidewalls and a pair of oppositclydisposed shoulders and an enlarged continuation of said split portionforming a kcyway bottomed on said shoulders and having opposing facesfor mating cngagcment with the faces of said key, internal screw threadsformed on said internal member, and an inturned flange on the upper endof said external member and in abutting engagement with said internalmember for holding the latter in position within said bore, the opposingfaces of the key and kcyway being in neutral condition to the axis turnwhereby the same amount of torque is required to loosen said out as totighten.

3. In combination with a threaded bolt, a lock nut comprising anexternal member defining a complete annulus and having an internal boretapering toward the bottom, the external surface thereof being formedfor cooperative engagement with a wrench, a key fixed in said borehaving opposing faces in line with the axis of rotation, and an innerface, a split annular internal member, extcriorly tapered for matingengagement in said bore, the inner split portion of said internal memberhaving parallel sidewalls, a pair of shoulders at the outer ends of saidsidewalls, the outer split portion being wider and deeper than the innerportion and forming a kcyway having a pair of faces for matingengagement with the faces of said key, internal screw threads formed onsaid internal member mating the threads on said bolt, and an inturncdflange on the upper end of said external member and in abuttingengagement with said internal memher for holding the latter in fixedposition within said bore, the inner face of said key in adjacentrelation to the largest diameter of the threads of the internal memher,the opposing faces of the key and keyway being in neutral condition tothe axis turn, whereby the same amount of torque is required to loosensaid nut as to tighten.

References Cited in the file of this patent UNITED STATES PATENTS

